Difference between revisions of "Metarules"

From Glottopedia
Jump to navigation Jump to search
Line 4: Line 4:
 
The ''Passive Metarule'' is used to generate for each VP-rule introducing a transitive verb a new lexical ID rule which introduces a passive verb form accompanied by the same phrases, except that the direct object replaced by an optional PP.
 
The ''Passive Metarule'' is used to generate for each VP-rule introducing a transitive verb a new lexical ID rule which introduces a passive verb form accompanied by the same phrases, except that the direct object replaced by an optional PP.
  
VP $\rightarrow$
+
VP $\rightarrow$ W, NP  VP[PAS] $rightarrow$ W, (PP[by])
 +
W is a variable ranging over a multiset of categories.
  
 
===Other Languages===
 
===Other Languages===

Revision as of 15:23, 20 September 2007

Metarules are used in Generalized Phrase Structure Grammar to capture structural generalizations in a similar way transformational rules did in earley transformational grammar. Unlike transformational grammars they don't map structural description onto (new) structural descriptions, but generate new lexical ID rules on the basis of given ones.

Example

The Passive Metarule is used to generate for each VP-rule introducing a transitive verb a new lexical ID rule which introduces a passive verb form accompanied by the same phrases, except that the direct object replaced by an optional PP.

VP $\rightarrow$ W, NP VP[PAS] $rightarrow$ W, (PP[by]) W is a variable ranging over a multiset of categories.

Other Languages